Nearly half of all American workers do not have paid sick leave, and half of these are more likely to go to work feeling unwell – or send an ill child to school – rather than take an unpaid day off.

These findings threaten to undermine President Obama's effort to have anyone exhibiting swine-flu-like symptoms stay at home for as many as four days. The emphasis on prevention and individual responsibility is a welcome departure from the punitive government actions – such as quarantines and forced vaccinations – called for under previous pandemic-response plans, some health experts say.

But for the 48 percent of Americans without paid sick leave, the policy presents a choice between two equally undesirable options: stay at home and lose money or go to work despite government exhortations not to. Businesses, too, say the situation leads to so-called "presenteeism," or the act of going to work while unwell, costing the economy $180 million a year, by one estimate.

Sen. Chris Dodd (D) of Connecticut announced Tuesday that he is preparing emergency legislation that would guarantee paid sick days for those diagnosed with the H1N1 virus.

"Families shouldn't have to choose between staying healthy and making ends meet," Senator Dodd said in a statement.

Dodd had also championed the Healthy Families Act, which sought to mandate an hour of sick time for every 30 hours worked. But that bill is stalled in Congress.